Illinois

By Zachary Goldsmith

• The Illinois state fossil is that of the Tully Monster ( Tellimonstrum gregarium )

• The Tully Monster was a small, snake-like organism with fins on its tail that helped it swim through the water.

• At the end of its neck was a small jaw that contained 8 sharp teeth for catching prey.

• Lived 340-280 million years ago.
• Lived during a period known as the Pennsylvanian geological period.

• Its fossils are preserved in rocks make up what used to be a large riverbed.
• Fossils are found in the Mazon Creek Deposits and open coal mines.

• Discovered in 1989 by Francis Tully
• Is the state fossil due to how common it is in Illinois and the fact that it is exclusively found in Illinois.

• Illinois State Fossil. Retrieved March 25, 2012 from

• State Symbol: Illinois State Fossil — Tully Monster (Tullimonstrum gregarium). Illinois State Symbols. Retrieved March 25, 2012 from
  http://www.museum.state.il.us/exhibits/symbols/fossil.html